Yet the most important factors in determining both temperatures and precipitation are the height and width of the Rocky Mountains, and the direction of the prevailing winds.The mountain ranges intercept air moving in from the Pacific and drain it of moisture.This gently rolling grassland is relatively dry and mostly treeless.
The parkland region predominates in central Alberta, forming a crescent to the west and north of the Prairie region and including most of the North Saskatchewan River drainage basin.
Low annual precipitation, high evaporation rates and fast runoff produce chronic water deficits in southern Alberta, varying from a moderate deficiency in the parkland region to a severe shortage in the short-grass prairie area.
Irrigation has been used in the latter area since the late 19th century.
Yet the amount of water available for irrigation itself is limited by the water flow in the South Saskatchewan River basin.
There have been recurrent proposals to divert water southward from the Peace and Athabasca rivers.
Lake Claire and Lesser Slave Lake are the two largest lakes entirely within Alberta.In the north the shorter season is offset by longer days and lower altitudes; and wheat is grown as far north as the Peace River.Resources Alberta is Canada's foremost energy-resource province.Climate Alberta's northerly latitude, stretching between lat. 60°N, puts the province in the northern cool-temperate zone.Cold winters and relatively short, cool summers are to be expected.It is home to the oil sands, or the largest oil reserve in the country (making it the third largest in the world), as well as vast amounts of natural gas and coal.